president barack obama will travel to boston on thursday for a service to remember the victims. he says this was an act of terror but americans cannot be terrorized. >> what we don't yet know is who carried out this attack or by, whether it was planned and executed by a terrorist organization foreign terrorist ofanizationor was the act a malevolent individual. >> the fbi is asking people in the boston area if they have seen or heard anything suspicious in the last few days. but he may be closer to home although this is a global inquiry. >> hundreds of people have gathered in boston, hold a vigil for the. victims of the the they met on boston common and sang songs and wrote messages. there was a heavy military presence at the vigil with dozens of members of the national guard. u.s. cities across the have been on high alert. officers have been on patrol outside the white house. all the victims of the attack, a flag on top the white house was to half mast on tuesday morning. coming up in the program, while aid workers in aleppo, syria, collect dozens of bodies, we will hear from a